A golfer must consider many variables when facing a putt. These variables including the slope(s) of the green, the type, cut, dampness and grain of the grass, the distance of the putt, and the weather (i.e. wind, rain, etc.). Data on many of these variables are available to the observant golfer. An analysis of all variables leads to a simultaneous decision as to how hard (the “speed”) and in what direction (the “line”) to strike the ball. It would seem that “all” that remains is for the golfer to step up to the ball and putt it along his intended line at his intended speed.
However, at least two residual problems plague the golfer. The first is an expected problem—he must not lose sight of his line as he steps up to execute the putt. The second is unexpected—the golfer in choosing the parameters of his putt typically assumes that, because his ball is spherical, the mass of the ball within the sphere will be completely balanced around the center point of the sphere. Thus, if he strikes the ball on the correct line at the correct speed the ball will travel on its intended course. While this is a reasonable assumption, it is generally not an accurate one. In particular, while most balls are virtually spherical (and those that are not can usually be weeded out by sight, or by mechanical means, e.g. dropping the ball through a ring repeatedly using different orientations for the ball), the center of mass cannot be immediately determined by sight and need not be located at the center of the sphere. This is problematic as it means that a perfectly executed putt may not travel along its intended path. Minor deviations mean missed putts.
Various devices exist to help the golfer with the first problem. These devices place one or more lines on golf balls to aid the golfer in aiming his ball once the intended speed and line have been determined. For example, U.S. Pat. No. 6,004,223 to Newcomb discloses a device that allows a golfer to draw a cross on a ball; and U.S. Pat. No. 5,564,707 to Dinh discloses a stencil consisting of various parallel and perpendicular lines that when placed on a ball is designed to aid alignment, the teachings of both of which are incorporated herein by reference.
Other devices attempt to deal with the second problem. These devices locate and mark the dynamic axis of a golf ball. For example, U.S. Pat. No. 4,546,644 to Beny, the teachings of which are incorporated herein by reference, discloses a device wherein: “[T]he dynamic axis of a sphere, e.g. golf ball, is located by spinning the sphere at high speed while it is supported on a low friction-bearing surface, thus allowing the desired stable axis to align itself with the spin axis. Markings indicative of the location of the stable axis are applied to the sphere.” In particular, proper use of Beny's device results in a line being drawn around the equator of the golf ball. U.S. Pat. No. 4,111,038 to Olson et al., the teachings of which are incorporated herein by reference, discloses a kit and a method for marking golf balls (with a pen forming a mark) wherein “the axis of the golf ball including the mark, should always be placed perpendicular to the plane of the striking surface.” Finally, U.S. Design Pat. No. Des. 323,301 to Cheng discloses a rotating axis marking unit for golf balls.
Despite these devices and methods for marking golf balls and determining dynamic axes, significant problems remain. Most golf balls come with markings placed on them by the manufacturer (e.g. the name of the manufacture, the type of ball, and an identification number), which are not intended to indicate a putting line or a dynamic axis. The addition of aiming lines can make the ball appear busy and make it difficult to successfully utilize the aiming lines. Interestingly, Dinh attempts to deal with this problem by incorporating into his stencil parts of the manufacturers markings. But since the manufacturer's markings do not account for the dynamic axis of the ball, clearly Dinh stencil will not be oriented optimally. The prior art devices find the dynamic axis by spinning the ball and marking the ball as it spins, thereby generating a circumferential line around the ball. Partial lines or markings other than lines (e.g. text) are not possible.
Many of the prior art devices and methods utilize non-permanent marking techniques, and all require significant work on the part of golfer.
Dave Pelz has addressed the problem of locating and marking the dynamic axis of a golf ball in his book Dave Pelz's Putting Bible (New York: Doubleday, 2000, pp. 203-212). Pelz suggests the use of a device (which he markets) to spin a golf ball and then hand marking a line along the equator. Pelz's device has a number of problems, including: (1) it can handle only one ball at a time; each ball must be spun and marked individually; (2) the special marker for hand marking the golf ball can be easily misaligned by the user during the process of marking, resulting in an incorrectly drawn equator; (3) the ink used for the device is temporary and rubs off onto the club head at impact; (4) the device only provides for an equator; it is not possible to draw any other configuration; (5) the Pelz equator line must be placed in addition to any markings already on the ball; and (6) no matter how careful one is, it is difficult to avoid knocking the ball out of alignment while marking the ball.
There remains a need for an effective method and device for marking golf balls for improved putting.